The US Patent Trademark Office (USPTO) has rejected 14 of Microsoft’s requests for the Patent Office's re-examination of unified communications vendor Avistar Communications 29 US patents.

Earlier this year Avistar questioned Microsoft’s motives for challenging 24 of its 29 US patents and admitted any legal battle could disrupt its business (CRN, 31 March).

At the time, four of Microsoft’s requests had already been rejected by the USPTO on procedural grounds.

Paul Carmichae, Avistar’s primary licensing advisor, said: “Data for the entire history of USPTO's re-examination activity indicate that only eight per cent of re-examination requests are rejected.

“While we believed that Microsoft's challenge to Avistar's entire US patent portfolio was without merit, we also recognised that the statistics relating to us avoiding a wholesale re-examination were against us.”

He added: “We are delighted that the Patent Office's review has resulted in this extraordinary result which validates and strengthens many of Avistar's most important patents, We expect that the nine patents that the USPTO has agreed to re-examine at this point also will be validated, and actually strengthened, through this process.”

Based on the history of the patents and the USPTO's response this week, Avistar is confident it will overcome any of the remaining re-examination requests that may be granted.

Avistar patents have industry wide applicability to audio, video and data unified collaboration products and services.

Simon Moss, chief executive of Avistar, said: “Avistar is obviously pleased with the USPTO's notification that challenges to the core 14 of our U.S. patents have been rejected. Avistar continues to remain focused on our business operations and have no further comment at this time with regards to our patent discussions.”